With per-domain transport, all mails received for these domains on your EC2 instance will be forwarded/relayed to your new server. For example, forward all emails received for domain example.com to new server newserver.com:

domain.com smtp:newserver.com

With iRedAdmin-Pro, you can configure per-domain transport in domain profile page, under tab "Relay". Screenshot for your reference:

With per-domain transport, all mails received for these domains on your EC2 instance will be forwarded/relayed to your new server. For example, forward all emails received for domain example.com to new server newserver.com:

domain.com smtp:newserver.com

With iRedAdmin-Pro, you can configure per-domain transport in domain profile page, under tab "Relay". Screenshot for your reference:

My user send a email to username@somedomain.com. This domain(somedomain.com) is not accepting my connection(My IP is blacklisted). I want to relay to another server, in another IP range to deliver this email.

I'm using iRedAdmin Pro in a EC2 instance, so far so good. But there are some domains that doesn't accept our connection or blocks our IP, as we are running in Amazon EC2(EC2 has history of spammers).

I don't want to change my running instance to another provider(Different IP range). I was thinking about forwarding(Mail relay) to another server, running in another provider, just for those domains. Is that possible?